Year	Percent
1992	12.96
1993	13.71
1994	16.32
1995	18.76
1996	19.33
1997	23.53
1998	27.1
1999	23.95
2000	20.71
2001	18
2002	15.57
2003	17.55
2004	17.21
2005	15.51
2006	16.37
2007	14.44
2008	14.04
2009	18.46
2010	17.09
2011	15.45
2012	14.86
2013	13.94
2014	13.79
2015	16.09
2016	16.46
2017	16.31
2018	16.96
2019	15.18
2020	16.96